In the case where a failure occurs in a machine or the like, a trouble shooting manual and a service manual (hereafter, collectively referred to as simply manual) are used for determining causes of the failure and repair methods, depending on the failure symptoms. For quickly restoring the machine or the like from failures, it is important whether items to examine causes of failures are arranged in a proper order in a manual or not. For example, with respect to a certain failure symptom, if causes that develop this symptom more frequently are described earlier in a reference order in the manual, it is possible to shorten the time required for a user or a service engineer of the equipment to find the causes of the failure, enabling quick recovery.
Accordingly, it is preferable that among causes of failures presumable from failure symptoms, such causes of failures as having higher probabilities together with repair procedures effective for such causes of failures are so described in the manual as to be arranged with priority in the manual. Conversely, a manual that is not described in such manner has a problem in that it takes a long time to determine causes of failures. Assume the case, for example, where check items not directly relevant to determine causes of failures are described with priority in a manual, and moreover where procedures to implement the checking are complicated and require much time. Considering that many service engineers do repair work using the manual in such case, an overall waste of time becomes too much to ignore.
In order to update manuals, however, a lot of labor and time are needed. Thus, conventionally, manuals generally are updated only in cases where they become non-functional as manuals unless they are updated, such as in the case where equipment specifications have been subjected to major changes. In other words, in the case of minor changes, manuals are sometimes not updated. Besides, updating of documents for new equipment models requires much time and manual work.